Stem mount for electric incandescent lamp



Jan. 8, 1957 c, MORGAN 2,776,852

STEM MOUNT FOR ELECTRIC INCANDESCENT LAMP Filed July 16, 1953 INVENTOR.0. c. Maze/21v.

United States Patent O STEM MOUNT non mgc rnro INCANDESCENT Donald C.Morgan, Orange, N. J., assignor to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application July 16,1953, Serial No. 368,317 3 Claims. c1. 287-20) tice in certain types ofelectric incandescent lamps to mount a heat shield in-the neck of thelamp bulb for the purpose of interrupting heat convection currents inthe bulb and to prevent overheating of the basal portion of the bulb.Heat reflectors or shields have heretofore most generally been supportedbeyond the end of the 9 glass press of the stem, upon the electrodes oroherwise, as exemplified by my prior application Ser. No. 248,377, filedSeptember 6, 1951, now Patent 2,664,513 issued on December 29, 1953, andmore recently it has been proposed in Patent No. 2,624,019 of December30; 1952, to transversely groove the press and slide a deflector orshield in the groove for support therein. Such a construction, however,has the serious drawback of establishing a transverse weakened areaopposite the bottoms of the grooves at which the stem tends to break,especially since the grooves have to be made with sharp corners next tothe bottoms thereof.

In its general aspect, the present invention contemplates theelimination of the disadvantages and defects of the prior art inprovision of a reflecting shield and improved means for mounting thesame.

More specifically, the invention proposes a structure which is readilymanufactured and easily assembled.

An essential characteristic of the invention resides in an improvedmounting arrangement for said shield and avoidance of a weakened line ofcleavage in the press.

More in detail, an object of the invention is to utilize inherentresiliency of the metal of the shield to admit the shield to itsultimate position and to retain it thereat.

Other objects, advantages and beneficial results will appear, as thedescription proceeds, to persons skilled in the art to which itappertains, both by direct recitation thereof and by implication fromthe context.

Referring to the accompanying drawing in which like numerals ofreference indicate similar parts throughout the several views:

Figure 1 is a lamp in elevation with my invention incorporated therein;

Figure 2 is a longitudinal central section of a neck portion of the lampas on line II--II of Fig. 1;

Figure 3 is a cross-section on line IIIIII of Fig. 2;

Figure 4 is a perspective view of a portion of the lamp stem; and

Figure 5 is a perspective view of the shield.

In the specific embodiment of the invention illustrated in said drawing,the reference numeral 1%) designates a usual sealed glass envelope orbulb of an electric lamp having a neck portion 11 provided with areentrant stem 12 sealed thereto at the basal end of the neck and stem.The inwardly directed end of the stem 12 is formed with a press 13through which are sealed a pair of leadin wires 14 connected at theirouter ends respectively to the shell 15 and center contact 16 of a base17. The base is of conventional type and is cemented as usual to thebasal end of the envelope 10. At their inner ends, the lead-in wires 14are connected to the opposite ends of a filament 18 which is heatedduring operation of the lamp. in the particular type of lamp shown, aglass rod or arbor 19 extends inwardly of the bulb from said press 13in. axial alignment with the stern, said arbor having a button 20terminating the inner endthereof and the button having a plurality ofsupport wires 21 projecting therefrom to separated locations on thefilament for giving support thereto in addition to the end supportafforded by the aforementioned lead-in wires 14. The assembly of stem,lead-in wires, arbor, filament and support wires is fabricated as anentity and generally referred to as the stem mount, and thereafterinserted in the bulb with the basal rims of the bulb and stem sealedtogether. Within the stem is an exhaust tubulation 22 which opens intothe bulb below the press and protrudes at the basal endof the stem whereit is tipped off after the interior of the bulb has been appropriatelyexhausted and refilled with desired gas. in general, the lamp structureso far described is in accordance with prior art manufacture.

The difierence of construction over the prior art is in the press 13. Incarrying out my invention, the press 13 is provided with a plurality ofspot retainers 23, in this instance illustrated as substantiallysemi-spherical indentations or pockets. I have shown two such pockets onone side of the press evenly spaced from the inner end thereof and asingle pocket on the opposite side of the press with like spacing fromthe inner end of the press but between the locations of the said twopockets.

A shield 24 of sheet metal and having general configuration of a disc,preferably of slightly less diameter than the inside diameter of theneck 11 of the bulb 10, is mounted on the press between the end of thestem and said retainers 23 of the press. For this purpose, the shield 24is provided with a radially disposed slot 25 extending inward from theperiphery of the shield with appropriate width and length to permit theshield to span the press and be substantially coaxial with the stem andbulb. The inward part of the slot 25 is provided with upstanding flanges26 at the marginal edges thereof. Inasmuch as the slot has a width asgreat as the full thickness of the press, there is ample materialenabling the flanges to be integral portions of the shield and bent upfrom the same when punching the disc to form the slot. The metalemployed, such as nickel or even aluminum, has adequate resiliency formaintaining said flanges in substantial parallelism but yet capable ofbeing temporarily sprung apart at their longitudinal free edges formounting purposes.

Said flanges 26 are provided with spot retainers 27 to cooperate withthe retainers 23 of the press. According to the illustrated embodiment,said retainers 27 of the flanges are constituted as projections stampedfrom the metal forming the flanges and project into the space betweenthe flanges in number and spacing to coincide with the spot retainers ofthe press. In its broad aspect, the invention contemplatesbump-and-socket form of cooperating retainers, and while the arbitrarilyselected embodiment provides the socket in the press and the bump on theflanges, a reversal of this arrangement may be employed by provision ofa socket in the flanges, and a bump on the press. In any event, as theshield is slid onto the press, the flanges spring outward to accommodatethe protrusion of the bump and when the sockets and bumps coincide withthe shield in place, the flanges spring back to substantial parallelismand the shield is held centralized by the cooperating retainers andmaintained perpendicular to the press by said flanges and retainers. Thethree point suspension by the retainers prevents Wobble in a directionacross the-broad faces of the press and in addition keeps the shieldfrom sliding laterally so that there will always be a gap between theentire periphery of the shield and the envelope. Furthermore, it isimportant to note that the character of retainers provided as aninherent part of the press avoids sharp edges by being rounded andintroduces no line of cleavage or other weakening of the press.

I claim:

1. A stein mount comprising a glass stem having an end thereof flattenedto form a press, a plurality of spot retainers constituted as integralparts of said press, a

shield having a radially disposed slot an inward portion whereofprovides flanges separated in parallelism a distance corresponding tothe thickness of the press and having inherent resiliency, said pressand flanges having cooperating bump and socket type of spot retainersadapted to be brought to registration by flexing said flanges toaccommodate the protrusion of the bumb retainers and to resilientlyreturn the flanges inwardly upon registration of the said retainers.

2. A stem mount comprising a glass stern having an end thereof flattenedto form a press providing opposite broad faces, a shield having a slotthe width whereof is substantially equal to the thickness of said pressbetween said faces, whereby the shield is slidable laterally onto saidpress, said press having curvilinear indentations constituting spotretainers, and said shield having resilient protrusions registering withand engaged in said indentations.

3. A stern mount comprising a glass stem having an end thereof flattenedto form a press providing opposite broad faces, a shield having a slotthe width whereof is substantially equal to the thickness of saidpre'ssbetween said faces, whereby the shield is slidable laterally ontosaid press, said press having curvilinear indentations constituting spotretainers, said shield having resilient flanges parallel to and inengagement with said faces, and said flanges having protrusions next tothe longitudinal edges thereof, said protrusions registering with andengaged in said indentations of the Press.

References Cited in the file of this patent UNITED STATES PATENTS1,694,154 Westendorf Dec. 4, 1928 2,164,901 Chilo July 4, 1939 2,532,162Goss Nov. 28, 1950 2,624,019 Leighton Dec. 30, 1952

